The present invention refers to valve means for governing the flow of fluids, and comprises a valve having a housing and a movable valve member, which is adjustable by servo means operated by a pressure fluid. It is common to use a lever, or some similar device, for directly actuating the servo means. It has also been proposed to use a solenoid or an electric motor to monitor the servo means.
The aim of the invention is to provide improved ways of governing the servo means so an exact positioning of the valve member is obtainable in a simple manner. A device according to the invention is easy to handle, is compact and may be manufactured at low costs. It is furthermore not sensible to most external disturbance factors, such as temperature acceleration and outside magnetic fields, and will not, itself, generate magnetic fields which would disturb possible other components in the plant where the device is included.